1. Field of the Invention
The present invention relates to the internal sealing of pipe leaks and especially to sleeve type packers for use with fast setting chemical grouts. The present packer apparatus is especially adapted for use in those systems in which a television camera in a waterproof housing may be pulled through a sewer line to detect leaks in the sewer pipe and assist in positioning the packer for sealing of the leak by remote control from a mobile unit located near an access to the sewer line.
Sewer pipes frequently develop leaks at the joints between sections of the pipe. Prior to the development of television cameras and internal pipe sealing equipment, the repair of subterranean pipe lines to correct the infiltration of water or the exfiltration of sewage had been to excavate along the pipe to locate the leak and repair the pipe. This, however, was time consuming and expensive or it was difficult to locate the exact site of a leak in the pipe. This resulted in experimentations for better ways of locating leaking joints and resulted in waterproof cameras such as TV cameras having lighting for pulling through the pipe line to examine the interior of the pipe line for leaks and structural damage. Once a fault or leak was located with a camera, a hole would be drilled to a spot near the leak and sealing material fed through conduits could repair the leak. This particular method and apparatus was described in the claims in U.S. Pat. No. 2,971,259 entitled METHOD AND APPARATUS FOR DETERMINING THE POSITION OF SEWER LEAKS, by Robert F. Hanau and Edward D. Toole and assigned to the assignee of the present invention. The next step in the evolution of repairing sewer lines involved the development of a mechanism for internally sealing a pipe leak having a packer movable within a pipe along its length for injecting a plugging material into the leak. Such a packer was described in U.S. Pat. No. 3,168,908 for a mechanism for the internal sealing of a pipe leak by James A. Zurbrigen and Jack C. Steinsberger and assigned to the assignee of the present invention. This type of sealing packer was used in association with an enclosed television camera to provide a method for sealing and repairing internal leaks in sewer lines by moving the packer along the pipe until a leak was detected by the television camera and a target located a fixed distance from the packer positioned under the leak, then advancing the packer a predetermined distance to place the packer directly over the leak and isolating the leak with the packer and injecting sealing material. This method was illustrated in U.S. Pat. No. 3,168,909 for a method of locating and sealing pipe leaks by James A. Zurbrigen and Jack C. Steinsberger and assigned to the assignee of the present invention. An improved packer mechanism for use for fast gelling chemical grouts was provided in the U.S. Pat. No. 3,103,235 entitled SLEEVE PACKER FOR CHEMICAL GROUTING by Edward D. Stringam, III and assigned to the assignee of the present invention in which a sleeve type packer was provided having a cylinder covered by an inflatable sleeve and banded at each end and having another band placed over the sleeve and in the middle thereof to provide a packer adapted for fast gelling grouts. One improved packer for use with fast gelling grouts was illustrated in U.S. Pat. No. 3,618,639 entitled PACKER FOR SEALING PIPE LEAKS by Daniel R. Daley and Clark J. Crooker and Thurman Soles and assigned to the assignee of the present invention, which illustrates a packer designed for rapid assembly of standard components and for rapid disassembly for repair or replacement of components. A method and apparatus for more precisely locating leaks in pipes utilizing a packer apparatus is described in U.S. Pat. No. 3,750,711 by James T. Conklin and James B. Rogers and assigned to the assignee of the present invention which packer uses air pressure or air flow fed into the void area in a pipe between the inflated end portions of a packer to detect leaking pipe joints.
The present invention provides for an improved packer apparatus which is especially useful in larger sewer lines in which the sewer pipe may have a greater diameter than the manhole opening and which may also require higher pressures in the inflatable sleeves and greater variation in pipe size for the use of a single packer. One prior art problem overcome by the present invention involves the banding or clamping of inflatable sleeves to cylinders which creates stress concentration where the sleeve may fail by breaking or coming loose due to the strain of expansion during inflation.